##
## This file is part of the sigrok project.
##
## Copyright (C) 2011-2012 Uwe Hermann <uwe@hermann-uwe.de>
##
## This program is free software; you can redistribute it and/or modify
## it under the terms of the GNU General Public License as published by
## the Free Software Foundation; either version 2 of the License, or
## (at your option) any later version.
##
## This program is distributed in the hope that it will be useful,
## but WITHOUT ANY WARRANTY; without even the implied warranty of
## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
## GNU General Public License for more details.
##
## You should have received a copy of the GNU General Public License
## along with this program; if not, write to the Free Software
## Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
##

# 1-Wire protocol decoder

import sigrokdecode as srd

# Annotation feed formats
ANN_LINK      = 0
ANN_NETWORK   = 1
ANN_TRANSPORT = 2

class Decoder(srd.Decoder):
    api_version = 1
    id = 'onewire'
    name = '1-Wire'
    longname = ''
    desc = '1-Wire bus and MicroLan'
    license = 'gplv2+'
    inputs = ['logic']
    outputs = ['onewire']
    probes = [
        {'id': 'owr', 'name': 'OWR', 'desc': '1-Wire bus'},
    ]
    optional_probes = [
        {'id': 'pwr', 'name': 'PWR', 'desc': '1-Wire power'},
    ]
    options = {
        'overdrive' : ['Overdrive', 1],
        'cnt_normal_bit'        : ['Time (in samplerate periods) for normal mode sample bit'     , 0],
        'cnt_normal_presence'   : ['Time (in samplerate periods) for normal mode sample presence', 0],
        'cnt_overdrive_bit'     : ['Time (in samplerate periods) for overdrive mode sample bit'     , 0],
        'cnt_overdrive_presence': ['Time (in samplerate periods) for overdrive mode sample presence', 0],
    }
    annotations = [
        ['Link', 'Link layer events (reset, presence, bit slots)'],
        ['Network', 'Network layer events (device addressing)'],
        ['Transport', 'Transport layer events'],
    ]

    def __init__(self, **kwargs):
        # Common variables
        self.samplenum = 0
        # Link layer variables
        self.lnk_state   = 'WAIT FOR FALLING EDGE'
        self.lnk_event   = 'NONE'
        self.lnk_fall    = 0
        self.lnk_present = 0
        self.lnk_bit     = 0
        # Network layer variables
        self.net_state   = 'IDLE'
        self.net_cnt     = 0
        self.net_search  = "P"
        self.net_data_p  = 0x0
        self.net_data_n  = 0x0
        self.net_data    = 0x0
        self.net_rom     = 0x0000000000000000

    def start(self, metadata):
        self.out_proto = self.add(srd.OUTPUT_PROTO, 'onewire')
        self.out_ann   = self.add(srd.OUTPUT_ANN  , 'onewire')

        # check if samplerate is appropriate
        self.samplerate = metadata['samplerate']
        if (self.options['overdrive']):
            self.put(self.lnk_fall, self.samplenum, self.out_ann, [ANN_LINK, ['NOTE: Sample rate checks assume overdrive mode.']])
            if   (self.samplerate < 2000000):
                self.put(self.lnk_fall, self.samplenum, self.out_ann, [ANN_LINK, ['ERROR: Sampling rate is too low must be above 2MHz for proper overdrive mode decoding.']])
            elif (self.samplerate < 5000000):
                self.put(self.lnk_fall, self.samplenum, self.out_ann, [ANN_LINK, ['WARNING: Sampling rate is suggested to be above 5MHz for proper overdrive mode decoding.']])
        else:
            self.put(self.lnk_fall, self.samplenum, self.out_ann, [ANN_LINK, ['NOTE: Sample rate checks assume normal mode only.']])
            if   (self.samplerate <  400000):
                self.put(self.lnk_fall, self.samplenum, self.out_ann, [ANN_LINK, ['ERROR: Sampling rate is too low must be above 400kHz for proper normal mode decoding.']])
            elif (self.samplerate < 1000000):
                self.put(self.lnk_fall, self.samplenum, self.out_ann, [ANN_LINK, ['WARNING: Sampling rate is suggested to be above 1MHz for proper normal mode decoding.']])

        # The default 1-Wire time base is 30us, this is used to calculate sampling times.
        if (self.options['cnt_normal_bit']):      self.cnt_normal_bit      = self.options['cnt_normal_bit']
        else:                                     self.cnt_normal_bit      = float(self.samplerate) * 0.000015 # 15ns
        if (self.options['cnt_normal_presence']): self.cnt_normal_presence = self.options['cnt_normal_presence']
        else:                                     self.cnt_normal_presence = float(self.samplerate) * 0.000075 # 15ns
        if (self.options['cnt_overdrive_bit']):      self.cnt_overdrive_bit      = self.options['cnt_overdrive_bit']
        else:                                        self.cnt_overdrive_bit      = float(self.samplerate) * 0.000002 # 2ns
        if (self.options['cnt_overdrive_presence']): self.cnt_overdrive_presence = self.options['cnt_overdrive_presence']
        else:                                        self.cnt_overdrive_presence = float(self.samplerate) * 0.000010 # 10ns
        # Check if sample times are in the allowed range
        # TODO
        self.time_base = float(self.samplerate) * float(0.000030)
        self.put(self.lnk_fall, self.samplenum, self.out_ann, [ANN_LINK, ['time_base = %d' % self.time_base]])

    def report(self):
        pass

    def decode(self, ss, es, data):
        for (self.samplenum, (owr, pwr)) in data:

            # Data link layer

            # Clear events.
            self.lnk_event = "NONE"
            # State machine.
            if self.lnk_state == 'WAIT FOR FALLING EDGE':
                # The start of a cycle is a falling edge.
                if (owr == 0):
                    # Save the sample number for the falling edge.
                    self.lnk_fall = self.samplenum
                    # Go to waiting for sample time
                    self.lnk_state = 'WAIT FOR DATA SAMPLE'
            elif self.lnk_state == 'WAIT FOR DATA SAMPLE':
                # Data should be sample one 'time unit' after a falling edge
                if (self.samplenum - self.lnk_fall == 0.5*self.time_base):
                    self.lnk_bit  = owr & 0x1
                    self.lnk_event = "DATA BIT"
                    if (self.lnk_bit) :  self.lnk_state = 'WAIT FOR FALLING EDGE'
                    else              :  self.lnk_state = 'WAIT FOR RISING EDGE'
                    self.put(self.lnk_fall, self.samplenum, self.out_ann, [ANN_LINK, ['BIT: %01x' % self.lnk_bit]])
            elif self.lnk_state == 'WAIT FOR RISING EDGE':
                # The end of a cycle is a rising edge.
                if (owr == 1):
                    # A reset cycle is longer than 8T.
                    if (self.samplenum - self.lnk_fall > 8*self.time_base):
                        # Save the sample number for the falling edge.
                        self.lnk_rise = self.samplenum
                        # Send a reset event to the next protocol layer.
                        self.lnk_event = "RESET"
                        self.lnk_state = "WAIT FOR PRESENCE DETECT"
                        self.put(self.lnk_fall, self.samplenum, self.out_proto, ['RESET'])
                        self.put(self.lnk_fall, self.samplenum, self.out_ann, [ANN_LINK     , ['RESET']])
                        self.put(self.lnk_fall, self.samplenum, self.out_ann, [ANN_NETWORK  , ['RESET']])
                        # Reset the timer.
                        self.lnk_fall = self.samplenum
                    # Otherwise this is assumed to be a data bit.
                    else :
                        self.lnk_state = "WAIT FOR FALLING EDGE"
            elif self.lnk_state == 'WAIT FOR PRESENCE DETECT':
                # Data should be sample one 'time unit' after a falling edge
                if (self.samplenum - self.lnk_rise == 2.5*self.time_base):
                    self.lnk_present = owr & 0x1
                    # Save the sample number for the falling edge.
                    if not (self.lnk_present) :  self.lnk_fall = self.samplenum
                    # create presence detect event
                    #self.lnk_event   = "PRESENCE DETECT"
                    if (self.lnk_present) :  self.lnk_state = 'WAIT FOR FALLING EDGE'
                    else                  :  self.lnk_state = 'WAIT FOR RISING EDGE'
                    present_str = "False" if self.lnk_present else "True"
                    self.put(self.lnk_fall, self.samplenum, self.out_ann, [ANN_LINK   , ['PRESENCE: ' + present_str]])
                    self.put(self.lnk_fall, self.samplenum, self.out_ann, [ANN_NETWORK, ['PRESENCE: ' + present_str]])
            else:
                raise Exception('Invalid lnk_state: %d' % self.lnk_state)

            # Network layer
            
            # State machine.
            if (self.lnk_event == "RESET"):
                self.net_state = "COMMAND"
                self.net_search = "P"
                self.net_cnt    = 0
            elif (self.net_state == "IDLE"):
                pass
            elif (self.net_state == "TRANSPORT"):
                if (self.collect_data(8)):
                    self.put(self.lnk_fall, self.samplenum, self.out_ann, [ANN_NETWORK  , ['TRANSPORT: 0x%02x' % self.net_data]])
                    self.put(self.lnk_fall, self.samplenum, self.out_ann, [ANN_TRANSPORT, ['TRANSPORT: 0x%02x' % self.net_data]])
                    self.put(self.lnk_fall, self.samplenum, self.out_proto, ['transfer', self.net_data])
            elif (self.net_state == "COMMAND"):
                if (self.collect_data(8)):
                    self.put(self.lnk_fall, self.samplenum, self.out_ann, [ANN_NETWORK, ['ROM COMMAND: 0x%02x' % self.net_data]])
                    if   (self.net_data == 0x33):
                        # READ ROM
                        self.put(self.lnk_fall, self.samplenum, self.out_ann, [ANN_NETWORK, ['ROM COMMAND: \'READ ROM\'']])
                        self.net_state = "GET ROM"
                    elif (self.net_data == 0x0f):
                        # CONDITIONAL READ ROM
                        self.put(self.lnk_fall, self.samplenum, self.out_ann, [ANN_NETWORK, ['ROM COMMAND: \'CONDITIONAL READ ROM\'']])
                        self.net_state = "GET ROM"
                    elif (self.net_data == 0xcc):
                        # SKIP ROM
                        self.put(self.lnk_fall, self.samplenum, self.out_ann, [ANN_NETWORK, ['ROM COMMAND: \'SKIP ROM\'']])
                        self.net_state = "TRANSPORT"
                    elif (self.net_data == 0x55):
                        # MATCH ROM
                        self.put(self.lnk_fall, self.samplenum, self.out_ann, [ANN_NETWORK, ['ROM COMMAND: \'MATCH ROM\'']])
                        self.net_state = "GET ROM"
                    elif (self.net_data == 0xf0):
                        # SEARCH ROM
                        self.put(self.lnk_fall, self.samplenum, self.out_ann, [ANN_NETWORK, ['ROM COMMAND: \'SEARCH ROM\'']])
                        self.net_state = "SEARCH ROM"
                    elif (self.net_data == 0xec):
                        # CONDITIONAL SEARCH ROM
                        self.put(self.lnk_fall, self.samplenum, self.out_ann, [ANN_NETWORK, ['ROM COMMAND: \'CONDITIONAL SEARCH ROM\'']])
                        self.net_state = "SEARCH ROM"
                    elif (self.net_data == 0x3c):
                        # OVERDRIVE SKIP ROM
                        self.put(self.lnk_fall, self.samplenum, self.out_ann, [ANN_NETWORK, ['ROM COMMAND: \'OVERDRIVE SKIP ROM\'']])
                        self.net_state = "TRANSPORT"
                    elif (self.net_data == 0x69):
                        # OVERDRIVE MATCH ROM
                        self.put(self.lnk_fall, self.samplenum, self.out_ann, [ANN_NETWORK, ['ROM COMMAND: \'OVERDRIVE MATCH ROM\'']])
                        self.net_state = "GET ROM"
            elif (self.net_state == "GET ROM"):
                # family code (1B) + serial number (6B) + CRC (1B)
                if (self.collect_data(64)):
                    self.net_rom = self.net_data & 0xffffffffffffffff
                    self.put(self.lnk_fall, self.samplenum, self.out_ann, [ANN_NETWORK, ['ROM: 0x%016x' % self.net_rom]])
                    self.net_state = "TRANSPORT"
            elif (self.net_state == "SEARCH ROM"):
                # family code (1B) + serial number (6B) + CRC (1B)
                if (self.collect_search(64)):
                    self.net_rom = self.net_data & 0xffffffffffffffff
                    self.put(self.lnk_fall, self.samplenum, self.out_ann, [ANN_NETWORK, ['ROM: 0x%016x' % self.net_rom]])
                    self.net_state = "TRANSPORT"
            else:
                raise Exception('Invalid net_state: %s' % self.net_state)


    # Link/Network layer data collector
    def collect_data (self, length):
        if (self.lnk_event == "DATA BIT"):
            #print ("DEBUG: BIT=%d t0=%d t+=%d" % (self.lnk_bit, self.lnk_fall, self.samplenum))
            self.net_data = self.net_data & ~(1 << self.net_cnt) | (self.lnk_bit << self.net_cnt)
            self.net_cnt  = self.net_cnt + 1
            if (self.net_cnt == length):
                self.net_data = self.net_data & ((1<<length)-1)
                self.net_cnt  = 0
                return (1)
            else:
                return (0)
        else:
            return (0)

    # Link/Network layer search collector
    def collect_search (self, length):
        if (self.lnk_event == "DATA BIT"):
            #print ("DEBUG: SEARCH=%s BIT=%d t0=%d t+=%d" % (self.net_search, self.lnk_bit, self.lnk_fall, self.samplenum))
            if   (self.net_search == "P"):
              self.net_data_p = self.net_data_p & ~(1 << self.net_cnt) | (self.lnk_bit << self.net_cnt)
              self.net_search = "N"
            elif (self.net_search == "N"):
              self.net_data_n = self.net_data_n & ~(1 << self.net_cnt) | (self.lnk_bit << self.net_cnt)
              self.net_search = "D"
            elif (self.net_search == "D"):
              self.net_data   = self.net_data   & ~(1 << self.net_cnt) | (self.lnk_bit << self.net_cnt)
              self.net_search = "P"
              self.net_cnt    = self.net_cnt + 1
            if (self.net_cnt == length):
                self.net_data_p = self.net_data_p & ((1<<length)-1)
                self.net_data_n = self.net_data_n & ((1<<length)-1)
                self.net_data   = self.net_data   & ((1<<length)-1)
                self.net_search = "P"
                self.net_cnt    = 0
                return (1)
            else:
                return (0)
        else:
            return (0)


#            # Transport layer
#            
#            # State machine.
#            if (self.lnk_event == "RESET"):
#                self.trn_state = "IDLE"
#            elif (self.trn_state == "IDLE"):
#                pass
#            elif (self.trn_state == "COMMAND"):
#                if (self.collect_data(8)):
##                    self.put(self.lnk_fall, self.samplenum, self.out_proto, ['FUNCTION COMMAND', self.net_data])
#                    self.put(self.lnk_fall, self.samplenum, self.out_ann, [ANN_NETWORK  , ['FUNCTION COMMAND: 0x%02x' % self.net_data]])
#                    self.put(self.lnk_fall, self.samplenum, self.out_ann, [ANN_TRANSPORT, ['FUNCTION COMMAND: 0x%02x' % self.net_data]])
#                    if   (self.net_data == 0x48):
#                        # COPY SCRATCHPAD
#                        self.trn_state = "TODO"
#                    elif (self.net_data == 0x4e):
#                        # WRITE SCRATCHPAD
#                        self.trn_state = "TODO"
#                    elif (self.net_data == 0xbe):
#                        # READ SCRATCHPAD
#                        self.trn_state = "TODO"
#                    elif (self.net_data == 0xb8):
#                        # RECALL E2
#                        self.trn_state = "TODO"
#                    elif (self.net_data == 0xb4):
#                        # READ POWER SUPPLY
#                        self.trn_state = "TODO"
#                    else:
#                        # unsupported commands
#                        self.trn_state = "TODO"
#            elif (self.trn_state == "TODO"):
#                if (self.collect_data(8)):
#                    self.put(self.lnk_fall, self.samplenum, self.out_ann, [ANN_NETWORK  , ['TRANSPORT DATA: 0x%02x' % self.net_data]])
#                    self.put(self.lnk_fall, self.samplenum, self.out_ann, [ANN_TRANSPORT, ['TRANSPORT DATA: 0x%02x' % self.net_data]])
##                self.put(self.lnk_fall, self.samplenum, self.out_ann, [ANN_NETWORK  , ['TODO unsupported transport state: %s' % self.trn_state]])
##                self.put(self.lnk_fall, self.samplenum, self.out_ann, [ANN_TRANSPORT, ['TODO unsupported transport state: %s' % self.trn_state]])
#                pass
#            else:
#                raise Exception('Invalid trn_state: %s' % self.trn_state)


#class onewire_device ():
#    def __init__ (self, scratchpad_size = 8):
#        pass
#    def reset (self):
#        pass
#    def data (self, data):
#        self.put(self.lnk_fall, self.samplenum, self.out_ann, [ANN_NETWORK  , ['TRANSPORT DATA: 0x%02x' % self.net_data]])
#        self.put(self.lnk_fall, self.samplenum, self.out_ann, [ANN_TRANSPORT, ['TRANSPORT DATA: 0x%02x' % self.net_data]])